THANKFULLY I have not had to use a urine stain cleaner in awhile here as our dog Bailey is 2.5 years and very thoroughly potty-trained now, and with Stubbin being our only cat, we do not have to deal with the sometimes common territorial kitty-peeing wars issue. However in my many years of professional career working with pets, fostering pets, and being a pet-parent to my own pets, I certainly have dealt with my fair share of pet URINE stains & smells in the past!
Perhaps like you, I had frustratingly tried many different products on the market which never lived up to their claims, but several years ago I learned of the importance of the product being an "enzymatic cleaner" as this process was needed to really LIFT the stain and smells form the fabric. I was recommended to try the Jaxon Galaxy brand cleaning tablets, and I am so glad that I did because a few years ago when I first moved in with Kelly and her kitty was dealing with anxiety with the changes he let his entre bladder go (picture 22 lb. Maine Coon cat-sized urine spot) on our couch! If I hadn't already had this cleaner on hand, I am not sure we would have been able to save that couch, but here it is today looks perfect and has not even the tiniest smell of urine; this stuff is really a miracle worker!
A GREAT trick is also, you can mix a 1/4 tablet to a 1/2 gallon of water and use in a spray bottle as well to directly apply to a urine-stained surface and let is soak hen wash off without needing a steam cleaner!